Field of the Invention
This invention relates to trenchers as used to form a continuous narrow opening in ground and, more particularly, to a handheld trenching apparatus that can be readily maneuvered, on and over, a ground surface by a user.
Background Art
Trencher technology for producing continuous, relatively shallow, narrow openings in different ground compositions/substrates continues to evolve. Such trenchers have in the past commonly been used to place wiring for low voltage components, such as landscape lighting and “invisible fencing”. With new technology, flexible hose for watering systems has been put in place above anticipated frost line depths, making it possible to use the same trenching technology for this particular application.
For the above shallow trench applications, and others, trenching apparatus are commonly required to form trenches along paths where there is a relatively narrow width. For example, outdoor lighting may require placement of wire between landscape items, such as trees, rocks, flowers, and bushes.
Heretofore, trenching units have been made with different basic designs. Commonly, a toothed, digging chain is advanced in an endless path and is plunged/pressed into a substrate and thereafter moved to define a trenchlopening along a desired path.
One version of such a digging apparatus is tractor mounted whereby an operator can form the trench continuously as the tractor is advanced. This version is designed primarily for open spaces wherein the tractor is not required to maneuver between or around objects and obstacles.
Another version also has a wheeled support and can be manipulated by a rear handle arrangement through which the trencher can be pushed and pulled. An exemplary design is shown in U.S. Pat. No. 4,429,477 (Tice et al.). While this version is smaller in size than those using tractors, and thus more versatile in terms of being able to trench in more confined areas, it still has limitations with respect to where it can access. For example, in flower beds or in areas where there are bushes and other types of foliage, maneuvering of the trencher may be precluded over a substantial length of a trench to be formed. In those areas inaccessible with the trencher, the trench is normally hand formed as a result of which the buried component may be more shallowly placed, which is an undesirable alternative. Further, hand digging generally produces a relatively wide opening in which the substrate material must be compacted to maintain the buried component in place.
A third version is essentially a variation of the second version, noted above. It is a more compact, lightweight arrangement on one or more wheels that permits access to tighter spaces. An example of such a design is shown in FIG. 9 in U.S. Pat. No. 6,760,983 (Fergusson et al.). However, the wheels are generally spaced far enough apart for stability that access to many locations where a trench is to be formed is limited. Thus, the user may default to hand digging and/or placing the component to be buried in a shallower than desired trench.
In the latter two designs, the power source is typically located relatively close to the cutting chain. The width of the power source, by itself, may be substantial whereby maneuvering in tight spaces may be difficult. An exemplary design with this limitation is shown in U.S. Pat. No. 3,054,198 (George et al.).
In spite of the well-known limitations of the prior art, a unit does not exist that has adequate versatility in terms of being easily handled and moved into tight spaces to obviate the need to hand dig trench portions.